Janby PCL1400 Service Code 121 help

SaskMan

Active member
May 22, 2023
25
Saskatchewan Canada
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Jandy Aquapure 1400
I bought this has 4 years ago which had this pool and all the components at the time of purchase so unsure how old the Janby PCL1400 is.

I have done the muratic acids wash / bath. Plugged it back in and everything seemed great. An hour or two later I see it has the service code 121.

Now this code seems to mean it could me any pile of issues. Too old, time to replace?

Does it stil make chlorine when it throws this code or is it not doing anything. Is there any way to test and see if it is actually producing chlorine?
 
121 usually means the cell is not connected to the SWG. This is because the terminals within the cell are corroded or the cable terminals are corroded. If the latter sometimes you can fix it with a new cable. If the former, the cell is toast. Post a pic of the cable end that connects to the cell and the terminals on the cell.
 
Will do. I will also add details of my pool below.
30K gal, IG vinyl, 1.5HP Pentair super max VS Pump. 2 large cartridge filters, Jandby PCL 1400 Salt Cell. Merely Krawler cleaner. No test kit
 
To test whether it's generating chlorine, set it to 100% boost and run the filter for 24 hours. Test your pool chlorine levels before and after. You should see an appreciable change.

I get 120 on my cell when it's failing in forward (generation mode). 121 when it's failing in reverse (descaling) mode. If you're only getting 121 then that may be a connection problem. Remove the black (DC cord) and inspect the contacts and pins. You can always buy a replacement cord to rule that out.

Given the age, it's probably the cell that's dying. In my experience (I am on my 3rd), when they go, they go. No amount of futzing around will resurrect them.

If it's the newer cylindrical cell, you shouldn't need to acid wash it.

Finally, I recommend against replacing with a knock-off cell. See my latest thread for how well that worked out for me :)
 
I dealt with this for weeks. Intermittent. 121 is low voltage, rather than 0 voltage which would be a dead cell. It was still generating chlorine.. Check your salinity and don't rely on the swg's sensor.
 
Here are some pictures. I did use some dielectric grease over the winter as that’s what our pool maintenance company told us to do. That’s the stuff you see there.

Does it matter which way you attach the plug to the salt cel? Appears as though it can go on both ways.
 

Attachments

  • IMG_9540.jpeg
    IMG_9540.jpeg
    516 KB · Views: 18
  • IMG_9544.jpeg
    IMG_9544.jpeg
    310.5 KB · Views: 18
  • IMG_9545.jpeg
    IMG_9545.jpeg
    405.9 KB · Views: 46
Here are a few more pics. Pics at 40% production and it shows the error code. After I plugged it back in and turned up the chlorination to 60% code is now gone. But i am guessing it wii come back right away.
 

Attachments

  • IMG_9541.jpeg
    IMG_9541.jpeg
    304.7 KB · Views: 5
  • IMG_9542.jpeg
    IMG_9542.jpeg
    263.4 KB · Views: 5
  • IMG_9543.jpeg
    IMG_9543.jpeg
    284.1 KB · Views: 5
  • IMG_9546.jpeg
    IMG_9546.jpeg
    366.9 KB · Views: 5
You can see the corrosion on the screws in between the pins.

Run the cell until it dies.

When you replace the cell also replace the cord.
 
Thanks. I found a spare pcl1400 in the attic area of the pool shed fron the previous owner. It doesn’t have corrosion by the pins. So I plugged that one in and that one giving me the same message. However - the “spare” salt cell I found is clearly used. So don’t know if it had previously died and wasn’t thrown out of in fact is a usable cel. So my next question is the cable. How do I test the cable before I spend $1500 on an entire new salt cel and cable? Is there a way to test just the cable to make sure it is doing what it needs to do?
 

Enjoying this content?

Support TFP with a donation.

Give Support
Test with a multimeter if there is any resistance in any of the wires or pins. You should have almost O resistance from one end of the cable to the other.
 
I suspect that the center pin or center plate has failed.

Look into the prong end of the cell at the center plate where the center pin connects to the center plate to see if you can see any damage or corrosion.

You can measure the amperage going to the cell with a clamp ammeter like shown in this thread.


If the voltage is good and the amperage is not good, the cell is probably failed.

You can remove the two screws and gently remove the compression plate that goes over the prongs to get a better check on the center pin.

aquapure-amp-measurement-3-png.337404
 
Last edited by a moderator:
It's DC powered, so my guess is that when you have the connector reversed, the controller thinks it's chlorinating your pool when in fact it's descaling the cell, and vice versa. Given that code 121 indicates low current in the reverse direction, while code 120 indicates low current in the forward direction, you may find your code changes to a 120 when you install in the correct orientation.

It does not matter.

The AquaPure has a 3 hour cycle time. The Aquapure reverses polarity every 3 hours.

 
It does not matter.

The AquaPure has a 3 hour cycle time. The Aquapure reverses polarity every 3 hours.


You're right - the manual says it doesn't matter. I didn't check.

I guess it's always generating chlorine - forward or reverse polarity. It's just by reversing they prevent scaling.

But this does mean if you reverse the connector you should see the error code change from 121 to 120.
 
Last edited:
This is the troubleshooting guide. There's a diagram for codes 120/121.

Don't forget to make sure you're salinity is not too low! And not with the cell's sensor.
What is the best thing out there to rest salinity. I’ve always just used the salt cell reading?
Also, below is what I use to manually check chlorine level. Anyone have experience with this?
 

Attachments

  • IMG_9547.jpeg
    IMG_9547.jpeg
    292.2 KB · Views: 5

Enjoying this content?

Support TFP with a donation.

Give Support
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.